To be honest, I was very sceptical of them at first as well; however, now I have my mind mapping software load at start-up - that is how much I need it. I put everything related to my ideas in it: links, notes, images, videos, pdf's, etc. One thing that you have to be careful of is that the maps for ideas can quickly grow to become huge, and I have now found it more beneficial to split large maps into smaller ones and just link through to them. They are also really useful if you have more than one idea on the go. Good software will allow you to set-up different styles too; this can be useful for simple flow diagrams.
